The Bay Area company building world’s largest vertical...

San Mateo’s Crop One, founded by Sonia Lo, expects its new facility in Dubai will produce 3 tons of leafy greens daily.

Photo: Courtesy Crop One

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Crop One of San Mateo will build the world’s largest vertical farming facility in a deal with Emirates Flight Catering. It will produce 3 tons of leafy greens daily.

Photo: Courtesy Crop One /

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Crop One of San Mateo grows leafy greens in its indoor facilities. One big advantage of vertical farming is that the sealed environment means no pesticides or herbicides are required.

Photo: Crop One

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Sonia Lo, founder of Crop One in San Mateo says, “The implications for what agriculture can do in terms of feeding more people are also incredibly exciting.”

Photo: Crop One

A small San Mateo company is building what is billed as the world’s largest vertical farm next year in Dubai, right on the runway that serves Emirates airline. The 50-foot-high sealed warehouse will produce 3 tons of leafy greens a day, without using a drop of what Sonia Lo calls “free energy” — otherwise known as sunlight — or soil, essentially recreating an optimized version of Central California in the Middle East.

“I love the fact that you’re redistributing the means of feeding back to where people actually are,” said Lo, CEO of Crop One Holdings in San Mateo, which since 2015 has provided fresh-cut lettuce and basil through Boston’s snowy winters from the company’s first vertical farm in Massachusetts. “The implications for what agriculture can do in terms of feeding more people are also incredibly exciting.”

Large-scale vertical farming, sometimes called indoor farming, uses LED lights and small doses of water and nutrients to grow leafy greens and herbs — and soon strawberries — year-round in otherwise unsuitable climates. Since the farming method can protect plants from the ravages of climate change, and may have the potential to recreate terroir for wine grapes or coffee, it’s attracting big investors. In the Bay Area, Crop One’s just-announced partnership with Emirates Flight Catering amounted to $40 million just to build the Dubai farm, and Plenty in South San Francisco, which will open a farm in the Seattle area this year, raised $200 million in funding last July.

Both companies are exporting two things the region is known for: technology and fresh-cut greens. Yet they both plan to also open facilities in Northern California as the Salinas Valley, known as America’s Salad Bowl, copes with labor shortages, drought and high land prices.

Matt Barnard, CEO of Plenty, which will sell the greens to Bay Area customers in a few months from its South San Francisco farm, points out that the majority of the world’s fruits and vegetables grow best in Mediterranean climates, of which there are just a handful around the world, including Salinas Valley.

“We’ve tapped out Salinas. There’s not a way to add capacity,” he said.

Barnard prefers to use the term indoor farming, not to be confused with growing in greenhouses, which use natural sunlight and dirt. In vertical farms, vegetables grow hydroponically — in a “soil-less medium” of water and nutrients. They sit on actual vertical walls, in the case of Plenty, or on stacked shelves with LED lighting overhead. The temperature- and humidity-controlled environment can be as simple as a shipping container within a larger warehouse.

Crop One of San Mateo grows leafy greens without soil or sunlight in hydroponic facilities using LED lights.

Photo: Crop One

Vertical doesn’t necessarily mean towering high, though; it does mean the plants are stacked closely and efficiently. The Dubai farm will be only about four or five stories tall, but at 130,000 square feet, it is large enough to produce greens for the 225,000 meals Emirates caterers produce daily for in-flight meals. Lo said she can produce the same amount on a single acre indoors that would normally require 400 acres of land, and that her company landed the deal because it has shown it can make vertical farming profitable.

But using LED lighting instead of “free energy” comes with high costs and a carbon footprint that can be comparable to shipping greens across the country. Running a 30,000-square-foot indoor farm in the New York City area would cost about $340,000 per year for power, lighting, heating and cooling, according to a recent report by Civil Eats. Because water can be filtered and reused in vertical farms, water use is only an estimated 1 percent of conventional farming.

Lo estimates that vertical farms cost one and a half times as much as traditional farms to operate, but that the cost to Emirates will be the same as what it currently pays for the vegetables shipped or flown from Spain, Italy or California. Plus, the greens will be available within 24 hours of harvest, she said, instead of the usual six weeks.

When it comes to the carbon footprint, a farm producing 1 ton of vegetables a day uses 3 megawatts of energy a year, Lo said, or enough to power roughly 2,200 homes. Greens produced by the Boston area farm, which sells under the FreshBox label, are carbon neutral when compared with greens transported from California, Lo said; they haven’t done a carbon analysis for Dubai yet. The company is planning to open three new farms in Connecticut and Texas soon, and is eyeing sites in Northern and Southern California as well as the Midwest, Georgia and Oklahoma.

One big advantage of vertical farming is that the sealed environment means no pesticides or herbicides are required, and the bacteria levels on the vegetables are much lower, which makes them safer as well as longer-lasting, reducing spoilage.

Then again, the same factors pushing vertical farming forward are also improving technology for traditional agriculture, such as remote sensors, software and drones that help farmers make irrigation more precise and improve soil health.

In November, the U.S. Department of Agriculture reaffirmed that hydroponic farms may use the USDA organic label, even though traditional organic farms and greenhouse growers fumed over that decision, arguing that soil is inherent to organic farming.

“A successful organic farmer is really a dirt farmer,” said Deverl Maserang, president of Earthbound Farm, which grows greens in San Benito and Monterey counties. “We've been farming some of our ranches for more than 20 years, and the longer you farm organically on the same soil, the richer and more productive it gets.”

As for the future of vertical farming, proponents are counting on further improvements to LED lighting to make it possible to profitably grow larger plants such as strawberries and table grapes. Fruit trees are harder, because of the extra energy required to grow their inedible branches and leaves, whereas most of the plant is edible in leafy greens.

Lo has been approached by spice companies to try to produce endangered tropical plants like vanilla, a crop largely grown in Madagascar and recently decimated by cyclones. The shortages have spurred major price swings across the globe.

Even if vertical farms do one day grow vanilla, they won’t replace the field-grown version, but rather, augment it. Still, that technology is likely years, if not decades, away, and would require huge investments from companies that depend on vanilla for their products.

Tara Duggan has written for the San Francisco Chronicle since 1999, starting out as a culinary intern in the Food & Wine department’s test kitchen. A food writer and recipe developer, she covers home cooking, restaurants, food trends, sustainable agriculture and food policy, all with a Northern California focus. A graduate of the California Culinary Academy, Tara also creates and tests recipes for feature stories in the paper. For 11 years, she wrote The Working Cook, a quick-cooking recipe column that appeared biweekly in The Chronicle. She wrote a cookbook based on the column in 2006 and has since written three other cookbooks.